Suomenlinna Kirkko was originally built in 1854. It was first consecrated as an Eastern Orthodox garrison church for Russian troops stationed at the sea fortress that was located on the island.

In 1918, the Orthodox church was converted into an Evangelical Lutheran church. The conversion was undertaken during a period when Finland was trying to assert its new-found independence from Russia.  

During extensive renovations, a more Western design was incorporated into the layout of the church, such as the removal of the onion domes of the four smaller towers. A competition ran to find the design for the church, this was won by architect Einar Sjöström. 

The redesigned church was reconsecrated in April 1929, but there was now something rather different about the building. The church’s central dome was redesigned into a lighthouse.

Initially, a gaslight was installed to provide light for the beacon, but today this has been converted to electricity. The church tower continues to function as a lighthouse for both air and sea traffic today.

Another fun fact, the signal blink pattern ”....” is Morse code for the letter “H” for Helsinki.